Seeding machines, such as row crop planters, include a plurality of planting units each configured to plant a row of seeds. A conventional planter has a plurality of row units that are typically equally spaced from one another. A twin row planter however, has two rows are spaced relatively close to one another, typically less than 10 inches (25.4 cm) apart and a larger spacing between on pair of twin rows and an adjacent pair of twin rows. Among the two rows of the twin row arrangement, it is necessary to synchronize the seed locations between the two rows. This is necessary to ensure that seeds in the twin rows are not a placed adjacent to one another but rather, are staggered relative to one another to optimize the space for the plant roots. Conventional planters are not concerned about the seed spacing synchronization between adjacent rows due to the large row spacing between all rows. As a result, mechanisms and methods to accomplish synchronization are needed for a twin row planter that have not been needed previously needed with conventional planters. One approach to provide the synchronization is shown in U.S. Pat. No. 7,377,221. This synchronization mechanism requires partial disassembly of the seed meter drive to adjust one seed meter relative to the other seed meter to provide the desired synchronization. Another approach to synchronization, practiced on twin row planter's available by Great Plains Manufacturing Inc., adjusts one the seed meter relative to the other by repositioning the seed meter drive sprocket relative to the drive chain. This requires removal of the chain from the sprocket and then turning of the seed meter to another position. The Chain is then placed back on the sprocket. Adjustment of the seed meter in both of these mechanisms is complex and/or messy, caused by handling of the lubricated chain. Furthermore, neither of these mechanisms are well-suited for use in a planter that utilizes a flexible rotatable drive shaft instead of a chain to drive each seed meter.